Chapter 434: The Great Wall’s Reinforcement
America’s tide-like attacks lasting half a year finally encountered a reef for the first time today in Guangnan’s Ashao Valley.
Such a battle damage ratio is obviously unacceptable to the US Military.
That’s only how many missiles.
If 20 missiles can cause three helicopters to crash and two helicopters to be severely damaged.
Then the war cannot continue.
Originally, North Vietnam mainly relied on the SA-2 compass surface-to-air missile system from the Soviet Union.
This is also the core of North Vietnam’s air defense system.
When North Vietnam used this system, according to the US Military’s post-war report “Vietnam War Air Combat Report,” North Vietnam launched about 9000 missiles in total, shooting down about 200 US Military airplanes.
Battle damage ratio at 45 to 1.
Now 4 to 1.
Efficiency improved 10 times.
After the news reached America’s command post in Saigon, McNamara realized from the direct reaction of the data that things had changed.
This absolutely cannot be achieved by the Soviet Union’s compass.
The duty intelligence officer pushed open the door of the operations room, pale-faced, and handed an encrypted telegram to McNamara.
“Minister, the report from Ashao Valley.
Our air formation lost five airplanes, satellite positioning system signal failed at the critical moment.
Not conventional surface-to-air missiles, they say this time North Vietnam’s missiles were like they had eyes, predicting our maneuvers!”
McNamara’s eyes narrowed into a slit, he pushed his black-rimmed glasses, staring at the data table on the telegram: flight path coordinates, electronic countermeasures activation time, missile trajectory estimate.
The table was roughly drawn with pencil.
In McNamara’s eyes, the numbers spoke.
20 missiles, hit rate up to 50%, jamming intensity exceeding known parameters of Soviet missiles.
Let me add here, 20 missiles hit five airplanes, it’s not a one-to-one relationship.
Not that one missile can only hit one airplane.
Actually, it may be multiple missiles hitting one airplane.
That is to say, China’s 20 Dragon Shadows hit a total of 10.
This number is quite astonishing.
“This absolutely cannot be achieved by the Soviet Union’s compass,” McNamara murmured: “Soviet missiles need to salvo dozens to bite an F-4, but here, 20 missiles tore apart our entire formation.
Look at this deviation data, their jamming targeted our navigation system.
Satellite positioning was supposed to be our ace, but now it failed to play its role.”
In the operations room, the map wall was pinned with colorful thumbtacks, the arrows representing US Military advances paused for the first time in Ashao Valley.
McNamara stood up, paced to the blackboard, and quickly sketched a simple chart with chalk.
He turned to his assistants and said: “This is absolutely not luck.
Fundamental changes are happening.
Assemble the team, have the ground forces move forward, we need to immediately dispatch ground forces to search for the opponent’s missile wreckage this time, we need further situation.
Those fragments are the best clues.”
Before departing for Saigon, at Nixon’s White House meeting, McNamara had strongly advised the president: “The Vietnam War is not hand-to-hand combat, we need to turn it into a battlefield of algorithms.
We have RAND Corporation, Bell Labs, IBM, Texas Instruments, what we need to do is use mathematics to conquer the jungle.”
Nixon eventually agreed.
It’s hard to imagine what magic McNamara had, this set of rhetoric convincing two consecutive presidents.
Therefore, when McNamara went to Saigon, he brought a large number of IBM System360 series large-scale computers.
And a professional engineer team from IBM, and a large number of mathematics professionals civil servants transferred from federal institutions.
Bringing all these people to Saigon together.
For McNamara, the only regret was not bringing Lin Ran.
But he still brought a mathematician, Zhou Yuanshen, professor in statistics in Columbia University Mathematics Department.
McNamara chose between Zhou Yuanshen and Chen Jingrun, on one hand because Chen Jingrun does number theory, statistics would fit his desired direction better.
After all, not everyone is like Lin Ran, all-round in the field of mathematics.
Besides being a Columbia professor, Zhou Yuanshen is also a researcher at IBM’s Thomas J. Watson Research Center.
On the other hand, because Zhou Yuanshen is a pro-ROC mathematician, who once served as assistant professor at National Taiwan University, while Chen Jingrun has not publicly expressed a stance, and teaches at a left-leaning university like New York City University.
So ultimately McNamara chose Zhou Yuanshen and brought him to the frontline.
In any case, in McNamara’s view, this is a substitute for the professor, mathematician, Chinese descent, Columbia professor, alright, it’s you.
After arriving in Saigon, the engineers expanded the temporary analysis center set up in the basement of the Military Assistance Command.
Walls plastered with flowcharts, air filled with fan noise and FORTRAN code printing sounds.
McNamara’s orders were quickly issued: an augmented company from the 1st Cavalry Division, 150 soldiers, equipped with M16 rifles, radios, and GPS positioning equipment.
Advance to the crash site in Ashao Valley under helicopter cover.
In the jungle, soldiers trudged through mud, rainwater soaking their boots, alert for possible ambushes at any time.
Company commander Lieutenant Tom Harrison ordered in a low voice: “Spread out and search, prioritize missile fragments, don’t touch explosives, mark positions.”
Two hours later, they found the first piece of wreckage in the scorched earth: a twisted aluminum casing circuitry board, surface etched with patterns, and a section of antenna.
The soldiers carefully packed it in canvas bags and airlifted it back to Saigon.
“Minister, our preliminary model shows,” IBM’s team head Harris Webber reported.
His beard disheveled, eyes bloodshot from staying up all night debugging.
Being sent to Saigon was bad enough.
If not for this being a White House order, IBM’s vice president personally assigned to him, and giving full vacation.
Harris Webber would never come to this ghost place no matter what.
Fortunately, progress was good before, McNamara privately told them many times that they could end this damned war before Christmas, and they would return home for Christmas with honor and results.
But now this episode has made everyone’s spirits tense.
US Military without air superiority, is it still the US Military?
When this war returns to the meat grinder mode, not to mention ending this year, whether they can win is unknown.
“Based on the radar echo data from these wreckage, this missile’s seeker is not pure infrared, it has analog adaptive filtering, able to switch frequencies in milliseconds.
Our satellite positioning signals were jammed, error jumped from centimeter level to meter level.
Undoubtedly, in the socialism camp, only China’s semiconductor technology can achieve such silicon-based circuitry density.
Only they in the semiconductor field can catch up to our AN/APQ-120.”
AN/APQ-120 is the aircraft fire control radar manufactured by Westinghouse Electric for McDonnell Douglas F-4E Phantom II, a fully solid-state radar, very compact, can be installed in the nose with the cannon.
Throughout the Vietnam War, America’s electronic warfare technology developed rapidly.
In the Rolling Thunder campaign of 1965, large-scale operations began, they carried external pods on airplanes, these external pods emit noise and deception signals to confuse enemy radar locks.
Waveform technology allows airplanes to generate signals at specific frequencies, simulating fake targets or covering real signals.
At the same time, they carry onboard receivers to detect enemy radar signals, allowing pilots to evade in advance.
In addition, they deploy metal chaff to create radar clutter, distract missiles, use heat decoy flares against infrared guided missiles, etc.
America’s electronic warfare technology is rapidly maturing.
On the Soviet side, by 1967, their electronic intelligence experts and equipment had to personally enter the field to maintain battlefield balance.
The current situation is that the past emergence of GPS broke the balance, China’s new missiles are trying to restore the balance.
Webber pointed to the chart projected by the projector: one curve representing Soviet missile ballistic trajectory; the other is Dragon Shadow’s firing path.
The latter accurately predicted the US aircraft’s right turn evasion.
The integration degree of hundreds of transistors on the circuitry board shows its technological maturity.
McNamara nodded, tapping the table.
“Model it.
Run Monte Carlo simulation for a thousand scenarios. Variables include wind speed, electronic countermeasures intensity, satellite signal redundancy channels.
Find the weaknesses.”
The engineers immediately got to work.
The next morning, McNamara convened a meeting with frontline commanders.
Generals sat around the long table.
“Gentlemen,” McNamara began: “What we face is not guerrillas, but technological progress.
Chinese people have intervened, their missiles have entered the field.”
Then, McNamara unfolded a report: “Based on engineers’ simulations and wreckage analysis, we should immediately adjust tactics, have B-52 switch to high-altitude blind drops, avoid low-altitude satellite positioning dependency; F-4 formations add Wild Weasel escorts, prioritize suppressing enemy radar; at the same time, urgently airlift more EA-6B electronic warfare aircraft from the homeland, equipped with newly programmed jamming pods, able to generate white noise against analog filtering.”
“The president has approved,” McNamara added, “we will extend data links to every airplane, real-time feedback loss rates, optimize flight paths.
The Pentagon will do the latest analysis for us in real time.
Our intelligence needs to be fed back to every frontline pilot’s hands.
Additionally, we need to continue dispatching army to search for more wreckage, every fragment is intelligence.”
Intelligence reached the Kremlin, besides about Dragon Shadow surface-to-air missiles, also including China’s request.
China hopes to take over part of North Vietnam frontline air defense.
In the past, this part of work was always handled by Soviet experts sent to the frontline.
Actually, China wanted to take over long ago.
Wanted to test their radar, even a whole set of equipment, on the Vietnam War frontline.
From Lin Ran obtaining US Military radar-related technical data, it has been over eight years (Christmas 1961).
In these eight years, China has long developed its own complete radar system.
After the small test of Dragon Shadow surface-to-air missiles, China urgently hopes to use this opportunity to test and adjust its own weapon equipment, and find directions for future optimization.
Just in the past, no suitable excuse, the Soviets were doing well, why change to you?
Now, the excuse has appeared.
Soviet equipment could initially go toe-to-toe with America, but America’s advantage is their R&D progress is too fast, iteration speed too fast.
According to Bernard Nalty’s “Tactics and Techniques of Electronic Warfare Surface-to-Air Missiles in the Air War Against North Vietnam 1965-1973 Electronic Countermeasures,” one of America’s Air Force tactics and techniques series monographs in Southeast Asia, the Soviets from 1970 began to fall behind America’s progress.
(US Air Force F-105D Thunderchief trying to evade V-75V SAM launched from North Vietnam SA-750 Dvina, image from US Air Force)
The Vietnam War tested the latest developments in both sides’ electronic countermeasures.
Initially, radar-controlled surface-to-air missiles and anti-aircraft guns had the advantage.
However, the US Air Force perfected countermeasures pods for fighter-bombers and equipped and armed airplanes to precisely locate and destroy missile sites.
These efforts, aided by long-range jamming and other services’ countermeasure aircraft, successfully restored a balance favorable to the offense.
In the original spacetime, they fell behind starting from 1970.
Culminating in the December 1972 B-52 strikes on Hanoi-Haiphong area Operation Linebacker II.
The entire wartime experience compressed into days, America completed the bombing.
But now, this time has been advanced.
Now, US Military’s advantage comes not only from GPS, but from overall technological progress.
Soviet air defense system is struggling in front of America.
North Vietnam frontline is in dire straits.
After Dragon Shadow’s small test, North Vietnam side is also full of expectations for China’s air defense system and radar equipment.
Kremlin, Leonard leaned back in his chair, squinting and smoking a cigarette.
At the table sat Marshal Grechko, Gromyko, and several KGB officials.
Piles of documents spread before them, mainly encrypted reports from Hanoi.
“Comrades,” Leonard began: “Yanjing’s comrades are stirring things up again.
Intelligence shows they are not satisfied with aiding missiles, now want to directly take over part of the frontline air combat.
They hope to deploy their air defense system in Lang Son Province.
Their engineers want to teach North Vietnam comrades to counter America’s Air Force.
Comrade Gromyko, what do you think?”
Gromyko adjusted his glasses, opened the report.
“Comrade Leonard, this is a tricky issue.
Chinese people claim their technology can fill our gaps. See Nalty’s analysis.
However, in fact their surface-to-air missiles have proven they can do it.
But Yanjing’s motives are clearly impure.
They claim to share semiconductor technology, intelligence shows their semiconductor technology has caught up to America’s Bell Labs.
If they take over the air defense zone from Lang Son to Ashao Valley, North Vietnam will depend more on China.
This is not good for us.”
Finally Gromyko added: “Perhaps favorable to the Vietnam War situation.”
After thinking for a moment, Leonard said: “We cannot publicly oppose.
North Vietnam comrades need aid, America’s progress is too fast, their overall technological progress, not just satellite positioning, but also those Wild Weasels and long-range jamming aircraft.
If Chinese people can delay the opponent’s iteration, let our SA-2 hold on for a few more months, perhaps by 1970, our new SA-3 can catch up.
But high risk, if Chinese people succeed, Hanoi will turn to Yanjing; if they fail, America will advance faster, our reputation goes down with it.”
Gromyko nodded: “I suggest private negotiations with Yanjing.
Have them provide technology to us to upgrade equipment, we continue to lead the aid.
Publicly support their intervention, but emphasize camp unity.
We need China’s technology to promote our multi-service collaboration, semiconductor technology is too important.”
By 1969, leaders of major countries all realized the importance of semiconductor technology.
Just how important exactly, they lacked a sufficiently clear concept.
Now from the electronic warfare on the Vietnam War frontline, it seems even more important than they thought.
At the end of the meeting, Leonard finalized the resolution: “Send a telegram to Hanoi, welcome China’s comrades’ supplementary aid.
But monitor them, Andropov, send more people to Hanoi, we need to find a way to obtain Chinese people’s technology.”
Secret transport planes landed in Lang Son Province valley, unloaded from the cabins no longer isolated missile crates, but complete air defense systems: twenty modified trucks, carrying China’s latest radar stations and electronic warfare equipment.
This time China’s lead Engineer Li appeared again, bringing more technicians, their toolboxes stuffed with transistor components and vacuum tube spares.
“Captain Nguyen,” Engineer Li unfolded the blueprint, explaining to Nguyen Van Thai, “Dragon Shadow is just the sharp blade, the Great Wall system I brought this time is the shield.
This system includes three core equipment: first is the Eagle Eye pulse Doppler radar station, volume like a truck, can scan in S-band and X-band, detection range up to 150 kilometers.
It can achieve multi-target tracking, distinguish US Military airplanes and chaff clutter, error less than 2 kilometers.
Unlike Soviet radars, it has analog adaptive filtering, able to automatically switch frequencies to avoid US Military jamming signals.”
Nguyen Van Thai nodded, his soldiers gathered around, faces full of curiosity.
On the blueprint, the second equipment is EW-1 area barrage jamming vehicle, a platform disguised as a supply truck, carrying low-power transmitters and receiver arrays.
EW is the English abbreviation for electronic warfare.
This vehicle’s core is aluminum casing circuit modules, able to generate white noise jamming, to counter US Military electronic countermeasures.
“It’s not just passive defense,” Engineer Li emphasized, “our circuitry has feedback loops, able to detect enemy signal strength, then simulate fake target echoes, filling their radar screens with ghosts.
Dealing with America’s Wild Weasel missions? We can lock back on their jamming sources, use servo antennas to guide missiles for counterattack.”
This set of means is on par with the US Military, even superior in jungle environments.
The third equipment is the integrated command station: an underground modular control room, connecting all units.
Inside installed with simple oscilloscopes and mechanical recorders, screens can display multi-channel radar data in real time.
“It’s the brain,” Engineer Li metaphorized, “integrated circuits process signal fusion, radar data, infrared signatures, and radio intercepts, together optimizing missile trajectories.
In short, we have full confidence in this system, it’s named after the Great Wall!”
This is the beginning of electronic warfare, America has changed opponents.
